POS1305 PEDIATRIC SAPHO SYNDROME: SINGLE ENTITY OR COMBINATION OF DIFFERENT DISEASES?
Authors: C. Matucci-Cerinic, G. Viglizzo, R. Caorsi, S. Volpi, C. Malattia, M. Gattorno
Journal: Annals of the Rheumatic Diseases (2022)

Background SAPHO is a heterogeneous autoinflammatory disease, characterized by bone and joint involvement and by a wide variety of dermatologic manifestations, including palmo-plantar pustulosis (PPP), acne, hidradenitis suppurativa (HS), pyoderma gangrenosum (PG), psoriasis, Snedd-Wilkinson disease and Sweet syndrome. In children, the osteo-articular manifestations are characterized by chronic recurrent multifocal osteomyelitis (CRMO), involving the metaepiphysis of the long bones and the axial skeleton, as in the adult form. The SAPHO treatment still today is a challenge, and no therapeutic guidelines are available in children: NSAIDs are frequently used as first line treatment for CRMO lesions, followed by bisphosphonates, methotrexate and biologic therapies. In the literature there are many case reports but only a few case series 1-3 , of which this is the largest in Europe (29 cases reported in China 4 ). Objectives to report the clinical and radiological features and the response to therapy of SAPHO children. Methods the clinical data (serological, imaging and therapy) of 13 SAPHO patients, followed between 2001 and 2021 at the Unit for Autoinflammatory diseases at the Gaslini Hospital were reviewed. Results 7/13 patients were male. At disease onset, acne-HS was present as the only manifestation in 8/13 patients while PPP was concomitant or subsequent to bone manifestations. The skin involvement was characterised by acne (comedonic in 3 cases, nodulo-cystic in 4 cases), PPP (5), HS (3), PG (1). Multifocal inflammatory bone lesions with axial or long bone involvement were both present in 92% of patients, whereas sternoclavicolar involvement was observed in 85% of patients. At disease onset all patients were treated with NSAIDS but only 4, with also PPP, achieved remission. In 7/13 patients, Methotrexate or salazopirin were used, and in 2/13 with severe painful bone lesions bisphosphonates were successfully employed. In the 5 PPP patients, the cutaneous involvement was mild and did not need treatment. In 9/13 patients, the skin manifestations required a therapeutic upgrade with biologics: Etanercept in 5 with partial result, Adalimumab in 6 had an optimal response, in 1 a partial response, even if requiring an increased dose (80 mg per week) and 1 was swapped to dapsone. Anakinra (3), ustekinumab and secukinumab (2) were not efficacious. It is to note that the 3 patients with comedonic acne were refractory to all treatments and needed multiple therapy cycling to achieve a partial remission only. Conclusion Our patients were characterised by well known SAPHO clinical manifestations. Despite the optimal therapeutic response of CRMO, comedonic acne was refractory to any treatment while PPP and nodulo-cystic acne achieved remission. This may suggest that the skin involvement in SAPHO may identify clinical phenotypes with a different response to treatments. References [1]Luzzati M, Ital J Pediatr. 2020;46(1):169. [2]Tlougan BE, Pediatr Dermatol. 2009;26(5):497 [3]Beretta-Piccoli BC, Eur J Pediatr. 2000;159(8):594 [4]Wu N, Clin Rheumatol. 2021;40(4):1487 Disclosure of Interests Caterina Matucci-Cerinic: None declared, Gianmaria Viglizzo: None declared, Roberta Caorsi Speakers bureau: Sobi, Consultant of: Novartis, Eli Lilly, Stefano Volpi: None declared, Clara Malattia: None declared, Marco Gattorno Speakers bureau: Novartis, SOBI